Automatic Derating - Danfoss VLT Midi Drive FC 280 Design Manual

Specifications
K4 Derating Curve
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0 2 4 6 8
Switching Frequency [kHz]
Illustration 7.6 K4 Derating Curve
K5 Derating Curve
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
0 2 4 6 8
Switching Frequency [kHz]
Illustration 7.7 K5 Derating Curve

7.12.2 Automatic Derating

The frequency converter constantly checks for critical
levels:
•
Critical high temperature on the heat sink.
•
High motor load.
•
Low motor speed.
•
Protection signals (overvoltage/undervoltage,
overcurrent, ground fault, and short circuit) are
triggered.
As a response to a critical level, the frequency converter
adjusts the switching frequency.
MG07B102
Design Guide
45C
50C
55C
10 12 14 16
45C
50C
55C
10 12 14 16
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